<div class="card {% if class %}{{ class | safe }}{% endif %}">
  
  {% if title %}
    <{{ heading | safe }} class="card-header">
      {{ title | safe }}
    </{{ heading | safe }}>
  {% endif %}
  <div class="card-body">
    <p class="card-text">
      {{ content | safe }}
    </p>
  </div>
  {% if footer %}
    <div class="card-footer text-muted">
      {{ footer | safe }}
    </div>
  {% endif %}
</div>